PSI - Issue 36

Victor Shapovalov et al. / Procedia Structural Integrity 36 (2022) 262–268 V. Shapovalov, I. Protokovilov, V. Porokhonko / Structural Integrity Procedia 00 (2021) 000 – 000

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Another pattern was obtained in impact tests. In this case, the weld metal showed 1.6 times higher values of impact toughness than the base metal. It is possible that this is due to the extremely large grain size of the weld metal (up to 9 mm), what led to the fact that the notch plane, in which the fracture occurred, crossed one or several grains. An increase in the impact toughness of the welded metal is also associated with a low content of interstitial impurities.

Table 3. Mechanical properties of the welded joint.

Yield strength, MPa

Tensile strength, MPa

Elong., %

Reduction of Area, %

KCU, J/сm 2

Component

929,9 806,4 817,2

971,4 874,7 878,0

16,9 10,6

44,1 34,2 23,4

38,7 61,9 55,9

Base metal Weld metal

9,3

HAZ

Thus, the mechanical properties of the welded joint, which are determined by the properties of the weld metal and HAZ, are primarily related to the grain size and microstructure and secondly, with the chemical composition and the content of harmful impurities. Large prior grain size and unfavorable acicular (α+β) microstructure in weld metal and HAZ have the most negative effect on the tensile strength and ductility (elongation and reduction of area) of electroslag welds.

Fig. 6. Fractographs of fractured impact test samples: a, b, c – base metal; d, e, f – HAZ; g, h, i – weld metal.